1. 1Virginia Commonwealth University, Richmond, VA 2Nike, Beaverton, OR
Association of isometric hip and ankle strength with frontal plane kinetics in females during running
Kathryn Harrison, MS;1 Bhushan Thakkar, PT, MS;1 David Pumphrey, BS, SPT;1 Gregory Crosswell, BS, SPT;1 D.S. Blaise Williams III, PhD, MPT, FACSM2
1Virginia Commonwealth University, Richmond, VA 2Nike, Beaverton, OR
Results
64 runners participated (Table).
No interaction effect of hip and ankle strength
No main effect of hip strength
Significant main effect of ankle strength (p=0.024, Figure)
Abstract
Frontal plane mechanics have been associated with running-related injuries such as patellofemoral pain. Strengthening and gait retraining programs aimed at reducing hip adduction during running have been shown to be effective at alleviating symptoms, however evidence of their effect on running kinematics is equivocal. It is possible that such programs exert their benefits through altering kinetics rather than kinematics in the frontal plane during running. Further, the contributions of the ankle to frontal plane mechanics have not been well studied. PURPOSE: To determine if hip and ankle strength are associated with frontal plane kinetics in female runners. METHODS: 64 healthy women running at least 16km per week participated in this study. Isometric hip abduction and ankle inversion strength were measured using a handheld dynamometer. 3D gait analysis was conducted as participants ran on an instrumented treadmill at 2.7 m/s. Participants were ranked in order of isometric strength of both the hip and ankle, and divided into tertiles of high, medium and low strength. 2-way MANOVA was used to determine the relationship between strength and peak moment, positive work and negative work in the frontal plane of the hip and the ankle. Tukey post-hoc tests were conducted where applicable (α=0.05). RESULTS: There was no significant interaction effect, or main effect of hip strength. There was a significant main effect of ankle strength on frontal plane kinetics (p=0.024). Specifically, the strong ankle group compared to the weak ankle group had significantly greater magnitude of peak ankle inversion moment (0.95(0.32) vs 0.68(0.22) Nm/kg, p=0.033), hip abduction moment (-2.78(1.02) vs -1.88(0.24) Nm/kg, p=0.002) and hip frontal plane positive work (0.27(0.19) vs. 0.13(0.03) W/kg, p=0.006). CONCLUSION: Isometric ankle but not hip strength is associated with kinetics in the frontal plane during running in females. Thus ankle strength should not be overlooked in clinical evaluation and treatment of runners.
Purpose
Determine whether hip and ankle strength are associated with frontal plane kinetics in female runners.
Methods
Healthy female runners recruited.
Isometric strength measured with a handheld dynamometer.
Hip abduction (ICC 0.84)
Ankle inversion (ICC 0.86)
Participants divided into stronger, medium and weaker tertiles.
3D motion captured while participants ran on an instrumented treadmill at 2.7m/s
Frontal plane kinetics: peak joint moment, positive work, negative work of the ankle, knee and hip
Effect of hip and ankle strength group on kinetics assessed using 2-way MANOVA (α=0.05).
Tukey post-hoc tests where applicable * **
Introduction
Frontal plane biomechanics associated with injury in runners.
Hip adduction1–2
Knee abduction moment3
Strengthening hip abductors reduced pain in PFPS.4
Hip abductor strength not associated with frontal plane kinematics.4,5
Strengthening may exert benefit by altering kinetics as opposed to kinematics.
Ankle strength may also play a role in frontal plane mechanics.
Figure. Frontal plane kinetics in female runners grouped according to ankle inversion strength. *p<0.05, **p<0.01
Conclusions
Ankle strength may be an important factor in frontal plane kinetics
Previous work associated greater ankle inversion moment with reduced knee abduction moment,6 but this was not found in this study
Runners may lose hip abduction strength with age
Runners who perform less weekly mileage (and perhaps more lateral or strength training activities) may have stronger ankle invertors.
Future work should assess the role of ankle strength in injury.
Table. Participant data
Age (yrs)
Height (m)
Mass (kg)
Yrs running
km/week
Ankle
Stronger
33(11)
1.65(0.05)
61.8(7.2)
10(8)
30(16)#
Medium
39(11)
1.66(0.06)
64.2(12.5)
11(8)
39(19)
Weaker
34(9)
1.63(0.08)
59.1(7.2)
12(7)
39(12)#
Hip
33(9)#
1.66(0.05)
63.2(9.1)
9(7)#
33(17)
34(10)
1.64(0.08)
62.2(10.5)
8(5)*
36(14)
38(10)#
1.64(0.05)
60.1(9.7)
13(9)*#
40(20)
*p<0.05, #p<0.1
References
1. Noehren, B., Hamill, J. & Davis, I. Med. Sci. Sports Exerc. 45, 1120–1124 (2013).
2. Noehren, B., Davis, I. & Hamill, J. Clin. Biomech. 22, 951–956 (2007).
3. Dudley, R. I., Pamukoff, D. N., Lynn, S. K., Kersey, R. D. & Noffal, G. J. Hum. Mov. Sci. 52, 197–202 (2017).
4. Ferber, R., Kendall, K. D. & Farr, L. J. Athl. Train. 46, 142–149 (2011).
5. Baggaley, M., Noehren, B., Clasey, J. L., Shapiro, R. & Pohl, M. B. Gait Posture 42, 505–510 (2015).
6. Sakaguchi, M., Shimizu, N., Yanai, T., Stefanyshyn, D. J. & Kawakami, Y. Gait Posture 41, 557–561 (2015).